1. Field of the Invention
The present invention relates to an active-matrix liquid crystal display device.
2. Description of Related Art
Recently, a liquid crystal display device is widely used, which drives display elements (liquid crystal elements) using liquid crystal for video display. In such a liquid crystal display device, arrangement of liquid crystal molecules is changed in a liquid crystal layer enclosed between substrates such as glass substrates, so that light from a light source is transmitted or modulated for display.
In the liquid crystal display device, active matrix drive is typically used. In such a drive method, frame reversal drive, in which polarity of voltage applied to liquid crystal is reversed every frame period, is performed to suppress degradation of liquid crystal. In addition, line reversal drive, in which polarity of voltage applied to liquid crystal is reversed every horizontal period (1H), is performed to suppress occurrence of flicker in each frame due to reversal of polarity of voltage applied to liquid crystal in the frame reversal drive. Furthermore, common reversal drive, in which polarity of voltage applied to a common electrode is reversed, is performed to reduce amplitude of a signal voltage applied to each pixel electrode.
The above previous drive methods are described in, for example, Japanese Patent Application, Publication Nos. 11-271787 and 2001-159877.